Heavy rain and flash floods have drenched Mississippi, prompting rescue operations, closures and evacuations including dozens of residents at a nursing home in the central part of the US state.

In statements posted to Twitter on Wednesday, the National Weather Service said flash flood warnings were in effect for several areas from Jackson, Mississippi's capital, to Meridian and southward to Laurel and Prentiss, with numerous reports of flooding.

Rankin County Sheriff Bryan Bailey said the Brandon nursing home's 42 residents had been moved to a safe room until conditions improve, WLBT-TV reported.

Rain has pummeled southern US states for the last three days. 

READ MORE:Wildfire-ravaged US states get flash flood warning

Mississippi deploys rescue boats to streets

First responders in the central Mississippi county also said they were working to rescue people from their homes amid Wednesday's downpour. 

Tammy Boykin, a Brandon resident, told the news station she had never seen flooding so severe in the eight years she has lived in the area. Bailey said the county had deployed one airboat, two regular rescue boats, and three high water rescue vehicles.

Leaders with the Canton Public School District in neighbouring Madison County announced schools would close early Wednesday due to the flooding and impassable roads.

There have also been several car crashes reported, many due to hydroplaning, according to WAPT-TV. 

A Jackson man told the news station he became stranded after his car stalled on a flooded street. He said he did not realise the road he was driving on was flooded until it was too late. He sat atop his car and waited until first responders arrived.

The Neshoba County Fairgrounds, home to an annual festival and cabins dating back to 1889, was flooded on Wednesday morning.

In south Mississippi, heavy rains led to flooding along area rivers, WLOX-TV reported.

The National Weather Service said it expects up to 5 centimetres of additional rainfall in central Mississippi through this evening. The heaviest rainfall has moved off to the east but light rain is still expected, the service said.

Missing hiker body found

The remains of a hiker swept away in flash floods in Utah were found on Wednesday after a number of hikers were hit by surging waters on Friday in Zion National Park. 

More rains are predicted in parts of Texas on Monday as forecasters predicted more precipitation throughout the southern part of the country for the rest of the week.

In New Mexico's Carlsbad Caverns National Park, around 200 people had to be evacuated after being trapped for several hours by rising waters after heavy rains pummeled the drought-hit southwest.

Elsewhere, footage showed children in Arizona being rescued from a school bus stranded by rising waters.